PRODUCTS OF ACETOUS FERMENTATION. 47 



requi res a Jarge suppl y } but the generators in general use in the 

 quick process are by no means so arranged as to be adequate to 

 ie^ theoretical demands. In fact it may be said that most of 

 them allow~only a limited change of air and consequently work 

 slower than they actually could. That the generators now in use 

 are deficient is conclusively proved by the numerous constructions 

 which have_ been proposed, especially in modern times, whose 

 chief aim isjx) afford a free passage to the air. 



The fact that considerable heat is developed in the interior of 

 the generator deserves consideration in connection with the heat- 

 ing of the manufactory. If the temperature of the latter is so 

 high as nearly to approach the optimum, i. e., the temperature 

 most favorable for the formation of vinegar, it may easily happen 

 that, in consequence of the vigorous oxidation of the alcohol, the 

 temperature in the interior of the generators is increased to such 

 an extent as to exceed this optimum, and the activity of the 

 vinegar ferment would immediately diminish and even cease 

 altogether. 



If, on the other hand, the temperature of the workroom is 

 kept too low, the generators act sluggishly and do not produce as 

 much as when the correct conditions are observed. But as by 

 raising the temperature of the workroom the activity of the 

 generators is increased, too low a temperature is less injurious to 

 the regular course of the process than too high a one. 



The optimum of the formation of vinegar is at about 86 F., 

 and hence the aim should be to maintain this temperature as 

 nearly as possible in the interior of the generator. The temperature 

 of the workroom must, however, be kept sufficiently low, so that 

 the optimum in the interior of the generator cannot be exceeded. 



Another factor may here be mentioned. The closer the tem- 

 perature in the interior of the generator approaches the optimum 

 mid the quicker the supply of air, the more alcohol and acetic 

 acid are lost by evaporation, or, in other words, the smaller the 

 yield ofacetic acid. By the skillful utilization of conditions the 

 manufacturer must aim to reduce this loss to a minimum, and 

 this can be best effected by a suitable arrangement of the work- 

 room. By regulating the change of air so that it is not greater 

 than absolutely necessary, the air will soon become so saturated 



